I just installed the expansion and for some reason Steam overlay refuses to work properly. I can hear message notifications fine, but pressing the overlay key (Pause / Break) doesn't bring up the overlay. Instead, I get a second mouse cursor - the normal Windows one. I can move the second cursor around just fine but I can't interact with the game until I hit the overlay key again. Oddly, Steam screenshots work just fine. I used to run the game with "-opengl" in the launch options for the overlay to work, but now it doesn't make a difference. This happens on both fullscreen and windowed mode, in any resolution. My PC runs Windows 7 Home 32-bit, my video card is an AMD Radeon HD 6850.